Laminatubus paulbrooksi, Rouse & Kupriyanova, 2021

Rouse, Greg W. & Kupriyanova, Elena K., 2021, Laminatubus (Serpulidae, Annelida) from eastern Pacific hydrothermal vents and methane seeps, with description of two new species, Zootaxa 4915 (1), pp. 1-27 : 14-18

Laminatubus paulbrooksi n. sp.

Figures 9–11

Neovermilia n. sp. — Levin et al. (2012)

Laminatubus n. sp. — Goffredi et al. (2020)

Material examined. Holotype: SIO-BIC A1416A, Jaco Scar , Costa Rica. For locality details see Table 2.

Paratypes: SIO-BIC A1397, Parrita Seep , Costa Rica, 1 spec. ; A1416B, Jaco Scar , Costa Rica, 1 spec. ; A1586, Jaco Scar , Costa Rica (prepared for SEM); A6165 , Pescadero Basin, Mexico, 3 spec. ; A8099A, Pescadero Basin , Mexico, 1 spec ; A8099B, Pescadero Basin , Mexico, 1 spec. ; A8099C, Pescadero Basin , Mexico, 1 spec. ; A9602A, Jaco Scar , Costa Rica, 1 spec. ; A9602B, Jaco Scar , Costa Rica, 1 spec. ; A9603, Jaco Scar , Costa Rica, 1 spec. ; A9908, Jaco Scar , Costa Rica, 1 spec.; A10072 , Jaco Scar , Costa Rica, 2 spec.; A11567 , Guaymas Basin , 1 spec.; A11568 , Guaymas Basin , Mexico, 1 spec.;A11569 , Guaymas Basin , Mexico, 1 spec. ; MZUCR 1505-01 , ex A8304, Jaco Scar , Costa Rica, 1 spec. ; MZUCR 1506-01 ex A9589, Jaco Scar , Costa Rica, 1 spec.

Additional material examined: Neovermilia globula holotype, AM W.3630, Australia, NSW, Cronulla , Port Hacking, 34°4’30”S, 151°8’48”E ; W.49842, Australia, NSW, Port Kembla , 34º27.5667’S, 150º55.7667’E .

Neovermilia cf. sphaeropomata AM W. 50911, R / V Investigator , voyage INV2015-C01, Op. 114-157, Great Australian Bight, 34º42.3333’S, 132º31.85’E.

Description. TUBE: white opaque, semi-circular to circular in cross-section, without wide flaring peristomes, some growth rings distinct, attached to the substrate throughout its length ( Fig. 9 ). Smooth low, sometimes slightly undulating medial keel and flattened attachment flange lacking alveoli present ( Fig. 10A, D ). External hyaline layer absent.

RADIOLAR CROWN: radioles not connected by inter-radiolar membrane, arranged into semicircles or incomplete spiral of up to two whorls ( Fig. 10B, D ). Stylodes and radiolar eyes absent.

PEDUNCLE: smooth cylindrical (circular in cross section), about twice as thick as normal radioles ( Fig. 10A, C, D ), gradually merging into opercular ampulla, constriction absent ( Fig. 10A, C, D ) Peduncle inserted on left side of radiolar crown, below line of radioles. Small distal latero-dorsal “winglets” (flattened distal parts of the peduncle) or pair of lateral wings proximal to opercular ampulla absent ( Fig. 10C, D ).

OPERCULUM: semi-transparent, completely globular or slightly flattened distally, opercular top slightly sclerotized, without distinct yellowish-brownish endplate ( Fig. 10A, C, D ).

COLLAR AND THORACIC MEMBRANES: collar high, clearly trilobed, with longer and wider ventral lobe and smaller lateral ones ( Fig. 10B , 11A ) and with entire edge, continuous with thoracic membranes as wide as thoracic tori, forming apron across anterior abdominal chaetigers. Pairs of small, wart-like protuberances of collar chaetiger or elongated tonguelets between ventral and lateral collar parts absent.

THORAX: with collar chaetiger and six uncinigerous chaetigers (specimen from A1586 with six uncinigerous segments on one side and five on the other), fascicle of collar chaetae separated from first uncinigerous chaetiger by a wide gap. Thoracic tori of the same length, gradually converging posteriorly, forming distinct triangular depression, but not touching each other medio-ventrally ( Fig. 10B ). Collar chaetae limbate only, no Spirobranchus - type chaetae present ( Fig. 11C, D ). Subsequent chaetae limbate, of two sizes, Apomatus -chaetae absent ( Fig. 11E ). Uncini along entire thorax saw-shaped, with 6–7 curved teeth, anterior fang slightly rounded to pointed ( Fig. 11F ). Pair of prostomial eyes absent.

ABDOMEN: with up to 80 abdominal chaetigers. Achaetous anterior abdominal zone absent, distinct chaetae with long shaft starting from first abdominal segment and continuing throughout entire abdomen. Tips of chaetae distinctly curved and hollow, made of two rows of pointed teeth, thus true trumpet-shaped ( Fig. 11G ). Distinctly longer capillary chaetae absent in posterior chaetigers. Uncini saw-shaped, with bluntly pointed fang and 6–7 teeth ( Fig. 11H ); posterior-most uncini rasp-shaped with 3–4 rows of teeth, bluntly pointed fang and 7–8 teeth in profile view posteriorly. Posterior glandular pad absent ( Fig. 11A ).

SIZE: length up to 45 mm. Radioles and operculum accounting for 2/5 of entire animal length.

COLOUR: white radiolar crown, yellow to reddish body ( Fig. 9 , 10 )

Etymology. This species was named for Paul Brooks in recognition of his long-term commitment and support of the Scripps Oceanographic Collections, particularly the Benthic Invertebrate Collection.

Distribution. Jaco Scar, Parrita Seep, Quepos Seep hydrothermal methane seeps on the Pacific Costa Rica margin (1400–1900 m), and Pescadero and Guaymas Basins (Gulf of California) methane seeps (1700–2400 m).

Remarks. Laminatubus paulbrooksi n. sp. is what was reported in Levin et al. (2012) as a new species of Neovermilia . This was based on a personal communication from the present authors and was based on the marked morphological differences from Laminatubus alvini that suggested it did not belong in that genus. The new species differs from L. alvini by the semi-transparent uniform operculum without a distinct yellowish-brownish endplate, presence of seven thoracic chaetigers and lack of Spirobranchus - type special collar chaetae. Laminatubus paulbrooksi n. sp. was reported in Goffredi et al. (2020) as showing a novel animal-bacterial symbiosis, driven by methane with distinct aerobic methane-oxidizing bacteria ( Methylococcales ), localized in the radiolar crown. There was a clear isotope signature showing that the worms were deriving nutrition from the bacteria.

Figures

FIGURE 9. Photos of Laminatubus paulbrooksi n. sp. in situ. At Jaco Scar, Costa Rica. Photo credit: ROV SuBastian, Schmidt Ocean Institute.

FIGURE 10. Photos of Laminatubus paulbrooksi n. sp. A–C—SIO-BIC A11567, A11568, A11569, Guaymas Basin, 1565 m; A—specimen in tube; B—ventro-lateral view of the thorax, C—close-up view of the operculum. D—specimen in tube, Alvin dive 4509, Jaco Scar, Costa Rica, 1866 m.

FIGURE 11. SEM of Laminatubus paulbrooksi n. sp. (SIO-BIC A1586). A—lateral view of a specimen with radiolar crown. B—close-up view of the thorax. C—collar chaetae. D—close-up view of collar chaetae. E—thoracic chaetae. F—thoracic uncini. G—close-up view of anterior abdominal true trumpet-shaped chaeta. H—anterior abdominal uncini.